Dynamic Ion‐Dipole Modulation in Stimuli‐Responsive Polymer Enables Ultra‐Safe Lithium Metal Batteries

Lithium metal batteries often generate substantial heat during operation due to persistent side reactions between the lithium metal anode and the electrolyte. Without effective regulation, this heat accumulation can lead to catastrophic thermal runaway. Here, an intelligent thermal regulation system based on a stimuli‐responsive poly(pentafluoropropyl acrylate) (PPFA) matrix is reported that precisely controls the release of LiDFOB via temperature‐dependent ion‐dipole interactions. Under normal operating conditions, strong PPFA‐DFOB − ion‐dipole interactions immobilize anions and facilitate the in situ formation of a robust solid electrolyte interphase, enabling Li||LiFePO 4 cells to achieve exceptional cycling stability over 500 cycles with 78.3% capacity retention at 1C. Under thermal abuse, the system dynamically switches to favor DOL‐DFOB − coordination, triggering the release of DFOB − and initiating 1,3‐dioxolane (DOL) polymerization, which results in a 34‐fold reduction in parasitic heat generation. This smart transition significantly improves safety metrics, achieving elevated self‐heating and thermal runaway onset temperatures of 108 and 286 °C, respectively, in 1.5 Ah pouch cells. This work establishes a new paradigm of molecular‐level thermoregulation via ion–dipole interaction control, offering a promising strategy for the development of inherently safer and high‐performance lithium metal batteries.